Electric motor



(No Model.) 2 Sheets-Sheet 1. 0. s. BRADLEY ELECTRIC MOTOR.

N0. 438,603. Patented Oct. 21, 1890.

WITNESSES:

2 SheetsSheet 2.

(No Model.)

G. S. BRADLEY.

ELECTRIC MOTOR.

No. 438,603. Patented Oct. 21, 1890.

is? j-w WlTN ESEIEEI UNITED STATES PATENT OFFICE.

CHARLES S. BRADLEY, OF YONKERS, NEIV YORK.

ELECTRIC MOTOR.

SPECIFICATION forming part of Letters Patent No. 488,603, dated October21, 1890.

Application filed August 13, 1890. Serial No. 361,905. (No model.)

To cbZZ whom it may concern.-

Beit known that I, CHARLES S. BRADLEY, a citizen of the United States,residing at Yonkers, in the county of IVestchester and State of NewYork, have invented certain new and useful Improvements in ElectricMotors; and I do hereby declare the following to be a full, clear, andexact description of the nvention, such as will enable others skilled inthe art to which it appertains to make and use the same.

This invention relates to the organization and construction ofalternating-current motors, belng particularly designed for applicat1onand use on single-current circuits.

If we take a disk I) having two circumferential slots, as in Figures 1and 2, and set it so that each slot surrounds or threads the lines offorce from alternate fields of force (represented in Figs. 1 and 2) bythe pole-pieces A and B, the disk becomes the seat of inducedorseeondary currents when the field-magnets are energized by analternating current, the paths of such currents being approximatelyindicated by small arrows on the disk, which constitutes two closedcircuits. If the disk be placed in the relation shown in Fig. 1, as soonas the alternating current is admitted to the field A B the rise andfall of potential therein sets up induced currents, and motion of thedisk results from the following principles: All the lines of forcemomentarily produced during one phase of alternation of magnetism in thefield-poles cause momentary induced currents, as indicated by thearrows. These currents pass from the center to rim and rim to center ofthe disk at the two unslotted portions shown, being from center to rimat one and from rim to center at the other at the same instant, andtherefore the currents generated by A and by B have common directionsthrough such unslotted portions, and are therefore attracted one by thenearest part of field A and the other by the nearest part of field B,and as these attractions take place at opposite sides of the shaft orcenter motion of the disk necessarily results. This motion continues inone direction till the disk is about in the position shown atFig.2.Motion then ceases, because the closed circuits of the disk are equallyat tracted by the oppositely-induced field-magnets, which neutralizeeach other. ciple of my invention is thus established,and continuousrotation of an element can be effected by subdividing andangularlydisplacing or commutating the field magnets.

My invention comprises a single-current field-magnet, an armature havingtwo or more closed induced circuits, and a commutating deviceforshifting the neutralpointin the fieldmagnet and producing progressivetorque.

My invention further comprises the arrangement and combination ofdevices substantially as hereinafter more fully described and claimed.

In the accompanying drawings, which form part of this specification,Figs. 1 and 2 are explanatory diagrams illustrating the funda mentalprinciple of my invention. Fig. 3 is an end elevation of a simple formof continuous rotary motor containing the elements of my invent-ion.Fig. I is a longitudinal section of a motor, illustrating a modifiedform of motor having a subdivided field wherein the polar lines of thefield are commutated; and Fig. 5 is a diagram of the circuits of Fig. 4.

In its simplest formthe motive device consists of the field-magnet A Band the slotted disk I), as in Figs. 1 and 2.

In Fig. 3 I use the disk Z), fixed on a shaft 0, provided with suitablebearings. On this shaft are the two insulated rings d e, on which bearthe respective brushes f g continuously. The shaft has fixed to, it thebrush-arm h, which in turn carries at diametrically-oppo site points theinsulated brushes t' it. These brushes bear on a stationary segmentalcollector or commutator 0, having its blocks looped in successively tothe subdivided fieldcircuit, so as to shift the polar line of thelatteraccordingly. Thefield-magnetiscomposed of a group of coresarranged in a circular series, each provided with its own coil, and thepole-pieces facing the path of the semicircular slot in the disk b. Ihave shown in Fig. 3 such a series of field-magnets facing one side ofthe disk only; butI prefer to have two series of such field-magnetsfacing each other and sowound that at any instant at which a given polehas north polarity the pole-piece opposite it on the other side of thedisk has south po- The prinlarity, and so on, so that the lines of forcepass directly from the pole-piece of one series to the pole-piece ot'the opposite series of fieldmagnets. The entire annular series offieldmagnets have their coils connected in series similarly to theconnections of a Gram me ring, so as to form a closed circuit, and.bet-ween each coil and the next adjoining one a loop is taken andconnected to the corresponding plate of the commutator O, which issupported in a stationary position by any suitable means so as to alwayspreserve thesame angular relations with the field-magnets. Obviously theline-current passing in at the brush f to ring at would go through brush70 into the commutator, and then dividing, one half would pass aroundthe magnet-coils on the right of the vertical line and the other halfaround the magnet-coils on the left of the vertical line, and at the topboth currents join together at the commutator and pass out at the brush1' through ring e into brush 9 and thence to line. Consequently at anygiven moment all the field-poles on one side of the vertical line willhave one polarity and all those on the other side of the vertical linethe opposite polarity. Thus in the position shown in Fig. 3 theneutralline will be a Vertical line drawn through the figure, and this linewill be the line of commutation and correspond with the operatingposition of the brushes 2' 7c. The disk I) being already advanced alittle toward the right, so as to correspond with Fig. 1, immediatelytakes up motion due to the preponderating attraction, as alreadyexplained, and this motion continues with a powerful torque until thebrushes have reached the next segment of the commutator, whereupon theneutral line is immediately shifted to the right and the position ofmaximum torque is again obtained, causing a further attraction of thedisk I) in the same direction, and the corresponding movement of thebrushes Us repeats this indefinitely as the disk rotates, owing to thedescribed commutation of the field-magnets, so as to keep the positionof maximum torque continuously ahead of the actual position of the disk.

In Fig. 4 is illustrated a form of motor wherein the disk I) is fixed toa suitable shaft and rotates between the adjacent ends of two circularseries of field-magnet poles, as already alluded to with reference toFig. 3. In this form of machine the field-magnets are commutated, asbefore, and the opposite polepieces will at any one instant be always ofopposite polarity, so that the lines of force between the two will passthrough the rotat ing disk I). I use laminated cores for thefield-magnets and join their back ends by means of the laminated yokesy, as shown in Fig. 4. Instead, however, of connecting the members ofthe field-magnet and commutating them, as shown in Fig. 3, I adopt thear-' rangement more fully shown in the diagram, Fig. 5. On the shaft androtating therewith 'I place the insulated rings d and e, as before, andon these suitable brushes bear and convey the line-currents to thecommutator. I also fix on the shaft the two semicircularcommutator-plates 1 and 2, plate 1 being connected to ring d and plate 2being connected to ring e. Surrounding the commutator is a ring 3 ofsuitable material and carrying at points corresponding to the angulardisplacement of the several field-magnets the brushes 4, 5, 6, 7, 8, 9,10, and 11. The plates 1 and 2 at their adjoining ends are separatedfrom each other by a gap at least equal in width to that of one of thebrushes, as shown in Fig. 5. These respective brushes are connected tothe corresponding ends ofthe field-magnet coils, which are designated inFig. 5 by the numerals 12, 13,14, 15, 16, 17,18, and 19. The other orouter terminals of all the field-magnet coils have a common connection,as illustrated by the circle m, which is obviously the that field-magnetcoils 19 and 15 are opencircuited. As the commutator 1 and 2 rotates,field-magnets12 and16 become open-circuited, and in thefurther rotationof the armature and commutator each diametrically-opposite set of coilsbecomes open-circuited, while the set of coils on each side of such linerespectively contribute opposite polarities to the circular range offield-magnet poles and the commutation proceeds with the same efiect asin Fig. 3, but with the additional-advantage that the short-circuitingefiect which would take place in the form shown at Fig. 3 when thebrushes connected to adjoining plates of the commutator is totallyabsent, and consequently the damaging sparking is entirely eliminated.

I claim as my invention- 1. An alternating-current electric motorcomprising a single-current field-magnet, an armature having two or moreclosed induction-circuits, and means for shifting the neutral line ofthe field.

2. An alternatingcurrent electric motor comprising a stationarysingle-current fieldmagnet, a rotating armature having two or moreclosed induction-circuits, and a commutating device for shifting theneutral line of the field.

3. An alternating-current electric motor comprising a rotating armaturehaving two or more closed induction-circuits, a stationary multipolarfield-magnet in inductive relation thereto and having its poles dividedin sign IIO on the respective sides of a diameter or neutral line, andmeans for continuously displacing such dividing-line in one direct-ion.

4. An alternating-current electric motor comprising at rotating armaturehaving two or more closed induction-circuits, a stationary inultipolarfield-magnet composed of an even number of eleetro-magnets arranged intwo or more parallel circuits so as to have I 10 all poles on one sideof a neutral line of one polarity of opposite sign to that of those onthe other side, and means for shifting the-neutral line between thegroups.

In testimony whereof I aflix my signatn re in presence of two witnesses.

CHARLES S. BRADLEY.

WVitnesses:

WILLARD L. OANDEE, RoBT. H. READ.

